Current File : //usr/src/kernels/3.10.0-1160.83.1.el7.centos.plus.x86_64/include/linux/i2c/pcf857x.h
#ifndef __LINUX_PCF857X_H
#define __LINUX_PCF857X_H
/**
* struct pcf857x_platform_data - data to set up pcf857x driver
* @gpio_base: number of the chip's first GPIO
* @n_latch: optional bit-inverse of initial register value; if
* you leave this initialized to zero the driver will act
* like the chip was just reset
* @setup: optional callback issued once the GPIOs are valid
* @teardown: optional callback issued before the GPIOs are invalidated
* @context: optional parameter passed to setup() and teardown()
*
* In addition to the I2C_BOARD_INFO() state appropriate to each chip,
* the i2c_board_info used with the pcf875x driver must provide its
* platform_data (pointer to one of these structures) with at least
* the gpio_base value initialized.
*
* The @setup callback may be used with the kind of board-specific glue
* which hands the (now-valid) GPIOs to other drivers, or which puts
* devices in their initial states using these GPIOs.
*
* These GPIO chips are only "quasi-bidirectional"; read the chip specs
* to understand the behavior. They don't have separate registers to
* record which pins are used for input or output, record which output
* values are driven, or provide access to input values. That must be
* inferred by reading the chip's value and knowing the last value written
* to it. If you leave n_latch initialized to zero, that last written
* value is presumed to be all ones (as if the chip were just reset).
*/
struct pcf857x_platform_data {
unsigned gpio_base;
unsigned n_latch;
int (*setup)(struct i2c_client *client,
int gpio, unsigned ngpio,
void *context);
int (*teardown)(struct i2c_client *client,
int gpio, unsigned ngpio,
void *context);
void *context;
};
#endif /* __LINUX_PCF857X_H */
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